1. Field of the Invention
The present invention relates to a method and an apparatus for reproducing a color image by printing a plurality of color dots.
2. Description of the Prior Art
Either the additive primaries (blue, green and red) alone or the subtractive primaries (cyan, magenta, and yellow) alone are generally used for color reproduction. Any desired color theoretically can be obtained by selectively overlaying the subtractive primaries, as is performed in multicolor printing. When all subtractive primaries are overlaid, a black image is produced. On the other hand, light beams of the additive primaries can be selectively mixed theoretically to produce any desired color, as is performed in color television. When all additive primaries are overlaid, a white image is produced. FIG. 1 shows the XYZ chromaticity diagram. An area 1 indicates the entire range of all possible colors; an area 2 indicates the range of colors which actually can be reproduced in color television using only the additive primaries; and an area 3 indicates the range of colors which actually can be reproduced in multicolor printing using only the subtractive primaries. Points B, G and R correspond to blue, green and red of the additive primaries, respectively. As may be apparent from FIG. 1, the additive primaries have a color reproduction range wider than that of the subtractive primaries since color characteristics of the subtractive primaries are not as good as those of the additives primaries. It should also be noted that the extent of the area 3 in FIG. 1 may vary slightly depending on the actual inks used.
However, when only the additive primaries are used, and the original to be reproduced has high luminance and high saturation, either luminance or saturation must be sacrificed in color reproduction. As a result, accurate image printing cannot be performed, resulting in poor image reproduction.